From: Bruce Richardson <bruce.richardson@intel.com>
To: Jerin Jacob <jerinjacobk@gmail.com>
Cc: dev@dpdk.org, "Jerin Jacob" <jerinj@marvell.com>,
"Pavan Nikhilesh" <pbhagavatula@marvell.com>,
"Abdullah Sevincer" <abdullah.sevincer@intel.com>,
"Shijith Thotton" <sthotton@marvell.com>,
"Hemant Agrawal" <hemant.agrawal@nxp.com>,
"Sachin Saxena" <sachin.saxena@oss.nxp.com>,
"Van Haaren, Harry" <harry.van.haaren@intel.com>,
"Mattias Rönnblom" <mattias.ronnblom@ericsson.com>,
"Liang Ma" <liangma@liangbit.com>,
"Peter Mccarthy" <peter.mccarthy@intel.com>,
"Honnappa Nagarahalli" <Honnappa.Nagarahalli@arm.com>
Subject: Re: [RFC PATCH] eventdev: ensure 16-byte alignment for events
Date: Thu, 5 Oct 2023 14:15:48 +0100 [thread overview]
Message-ID: <ZR63BJYKk9uaPa6B@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <CALBAE1PijrKLyt6KvLtVo84nL5Dg+7ESQR2UqhB5zcceJNwy6Q@mail.gmail.com>
On Thu, Oct 05, 2023 at 06:41:34PM +0530, Jerin Jacob wrote:
> On Thu, Oct 5, 2023 at 6:01 PM Bruce Richardson
> <bruce.richardson@intel.com> wrote:
> >
> > On Thu, Oct 05, 2023 at 12:51:00PM +0100, Bruce Richardson wrote:
> > > The event structure in DPDK is 16-bytes in size, and events are
> > > regularly passed as parameters directly rather than being passed as
> > > pointers. To help compiler optimize correctly, we can explicitly request
> > > 16-byte alignment for events, which means that we should be able
> > > to do aligned vector loads/stores (e.g. with SSE or Neon) when working
> > > with those events.
> > >
> > > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> > > ---
> > > lib/eventdev/rte_eventdev.h | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/lib/eventdev/rte_eventdev.h b/lib/eventdev/rte_eventdev.h
> > > index 2ba8a7b090..bb0d59b059 100644
> > > --- a/lib/eventdev/rte_eventdev.h
> > > +++ b/lib/eventdev/rte_eventdev.h
> > > @@ -1344,7 +1344,7 @@ struct rte_event {
> > > struct rte_event_vector *vec;
> > > /**< Event vector pointer. */
> > > };
> > > -};
> > > +} __rte_aligned(16);
> > >
> >
>
> + Eventdev driver maintainers for review and for performance testing.
>
> > Looking for feedback on this idea - hence the fact this is going as an RFC.
>
> Are you seeing any performance improvement ? Look like only DLB2
> driver only using SEE or AVX512 instructions.
>
The idea would be that the driver code (and eventdev code) should not need
to use SSE directly. If we mark the event struct as aligned, it should help
encourage the compiler to use these instructions under-the-hood. For
example, when copying an event, the compiler should be emitting 128-bit
loads and stores for most platforms.
/Bruce
next prev parent reply other threads:[~2023-10-05 13:22 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-05 11:51 Bruce Richardson
2023-10-05 12:06 ` Bruce Richardson
2023-10-05 13:11 ` Jerin Jacob
2023-10-05 13:15 ` Bruce Richardson [this message]
2023-10-06 7:19 ` Jerin Jacob
2023-10-05 12:12 ` Morten Brørup
2023-10-05 13:02 ` Bruce Richardson
2023-10-06 9:37 ` [PATCH v2] " Bruce Richardson
2023-10-06 9:45 ` [PATCH v3] " Bruce Richardson
2023-10-06 10:13 ` Morten Brørup
2023-10-06 10:16 ` Jerin Jacob
2023-10-06 10:19 ` Bruce Richardson
2023-10-06 10:24 ` Jerin Jacob
2023-10-06 10:27 ` Bruce Richardson
2023-10-06 10:16 ` Bruce Richardson
2023-10-06 10:35 ` Morten Brørup
2023-10-06 10:44 ` Bruce Richardson
2023-10-06 10:29 ` [PATCH v4] " Bruce Richardson
2023-11-12 0:01 ` Stephen Hemminger
2023-11-12 8:30 ` Morten Brørup
2023-11-12 23:31 ` Stephen Hemminger
2023-11-13 7:58 ` Morten Brørup
2024-01-19 21:05 ` Tyler Retzlaff
2023-10-06 12:15 ` [RFC PATCH] " Mattias Rönnblom
2023-10-06 12:19 ` Bruce Richardson
2023-10-06 12:29 ` Mattias Rönnblom
2024-01-19 22:30 ` Stephen Hemminger
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